Tube-mill



R. C. NEWHOUSE.-

TUBE MILL.

APPLICATION FILED FEB. 2|. 191e Patented Dec. 13, 1921.

UNITED STATES PATENT OFFICE.

RAY C. NEWI-IOUSE, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO ALLIS-CHALMERS MANUFACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF DELAWARE.

TUBE-MILL.

Specification of Letters Patent. Patented Dec. 13, 1921.

Application filed February 21, 1916. Serial No. 80,068.

To all whom it may concern Be it known that I, RAY C. NEWHOUSE, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of lVisconsin, have invented a certain new and useful Improvement in Tube-Mills, of which the following is a specification.

This invention relates to improvements in the construction of tube mills and is especially applicable toinstalled tube mills which, in accordance with the invention, may be reconstructed with very little change to materially increase their capacity and efliciency. I

"An object of the invention is to provide a tube mill which is simple in construction andeflicient in operation. One of the more specific objects is to provide simple and eflicient means for materially increasing the capacity and efficiency of a tube mill of the ordinary type. A further object is to pri-- vide means for permitting utilization of an efficient charge of heavy grinding bodies in a tube mill which has been designed primarily for operation with a charge of rela:

tively light grinding bodies.

It has been customary to utilize relatively long tube mills provided with either a single comminuting chamber containing flint pebbles, or a series of comininuting chambers containing flint pebbles and iron grinding bodies in successive chambers, for the purpose of grinding various materials, such as ores and cement making materials. The fact that flint pebbles were utilized as a comminuting medium in these mills of the prior art, flint pebbles constituting a relatively light grinding charge, permitted relatively light construction of the mills and of the mechanisms for driving the same. A great number of these tube mills of light design are at present in operation and in condition for further service. Since the installation of these mills it has been found that the efliciency of iron bodies as a grinding medium is considerably higher than that of flint pebbles. In order to permit utilization of the light tube mills and to secure the benefit of the iron grinding bodies, it has been attempted to substitute for the flint pebbles, charges of iron grin-ding bodies having substantially the same weight as the pebble charges previously employed. Such substitution was not permissible in cases where the driving power of grinding bodies for the. flint pebbles in...

these mills of the prior art was found to increase thecapacities and the efficiencies thereof, it is well known that the most efficient charge of grinding bodies is one extending in proximity to the axis of the mill. The mills and driving mechanisms as installed are, however, of such light design that they would be incapable in most cases of withstanding the load if charges of iron grinding bodies extending to the axes of rotation were distributed throughout the entire lengths of the mills. In many cases the power required to drive a mill thus loaded would not be available.

With the use of the present invention acharge of heavy grinding bodies extending in proximity to the axis of the mill may be placed in any of thetube mills of the driving mechanism thereof. With the useof the present invention the power required is also reduced to a minimum. The inven- 1 tion is also applicable in cases-whereit isdesired to install mills, capable of having their capacity increased, the use of the prescut invention permitting such increase in" capacity without necessitatingany substantial changes in the mill construction. v

A clear" conception of an embodiment of the invention maybe had by referring to the drawing accompanying and forming a part of this specification in which like reference characters designate the sameor similar parts 1n the various vlews.

Figure 1 is a transversexvertical sectionthrough a tube mill" having-the invention.

embodied therein.

Fig. 2 is a transverse vertical section through the mill disclosed in Fig. 1, the section being taken along the line II-II of Fig. 1 looking in the direction of the arrows.

Fig. 3 is a fragmentary transverse vertical section through a mill having the invention applied in another form.

The tube mill comprises essentially a rotary drum 1 having end heads 8, 9, and feed and discharge trunnions 10, 11, respectively. The trunnions 10, 11, are supported in suitable bearings 12, located adjacent the ends of the drum 1. The drum 1 may be rotated .in any suitable manner by means of the is provided with a charge of heavy comminuting bodies 35, disclosed as metal ballsextending in proximity to the mill axis. The comminuting chamber 4 is located adj acent the discharge trunnion 11, and is provided with a charge of heavy comminuting bodies 36, disclosed as metal balls of somewhat smaller diameter than the bodies 35 of the comminuting chamber 2 and also extending in proximity to the mill axis. The comminuting chambers '2, 4, are provided with suitable wearing liners 7 The end of the chamber 4 adjacent the discharge trunnion 11 is provided with a suitable discharge screen 21 and elevating vanes 13 located between the screen 21 and the head 9, the vanes 13 being adapted to discharge the fine product into the disharge trunnion 11.

The spacing chamber 3 is located between the adjustable partitions .5, 6, and in the disclosure of Figs. 1 and 2, is provided with helical blades 20 forming a conveyer secured to the interior of the drum 1. The partitions 5, 6, are held in spaced relation by means of a suitable strut 14' which is adjustable in length by means of suitable adjustable devices 15 to vary the distance between the partitions and hence the relative lengths of the chambers 2, 3, 4. Access to the interior of the chamber 3 for purposes of inspection and insertion of the partitions 5, 6, is permitted upon removal of a manhole cover 19. Other manholes may be provided for permitting access to the interior of the other chambers if so desired. The material leaving the comminuting chamber 2 pames through perforations 16 in the partition 5 and is urged through the chamber 3 by means of the helical conveyer blades 20. At the discharge end of the spacing chamber '3, the material is delivered by the blades 20 into the path of the radially disposed elevating vanes 17 which deliver the material from. the chamber 3 into the chamber 4, through a central opening in the partition 6.

In the disclosure of Fig. 3 the drum 27 is. divided into comminutin chambers 32, 34, by means of the adjustabi partitions 26, 28. The partition 26 comprises a pair of spaced disks, one of which is provided with perforations 29 and the other of which is provided with a central opening. Radially disposed lifting vanes 25 are located between the disks and are adapted to elevate and to deliver material from the chamber 32 through the openings 29, through the central opening in the other disk. The partition'28 comprises a pair of spaced disks each having a central opening therein and radially disposed lifting vanes between the disks. The disk 30 adjacent the chamber 33 is provided with one or more openings 23 adjacent the periphery thereof, which openings are provided with scoops adapted to pick up any material which enters the chamber 33 and to convey this material into the path of the lifting vanes 31. The partitions 26, 28, are spaced and. connected by means of a conduit or tube 24 located centrally within the drum 27 and having a screw conveyer therein. The tube 24 may be formed of telescopic sections to permit adjustment of the length thereof The screw conveyer is secured to the partition 28 and is rotatable with the mill. Access to the in- ,terior of the chamber 33 is permitted upon removal of a manhole cover 39. Other manholes may be provided for permitting access to the other chambers if so desired. The screw conveyer 22 is adapted to transport material discharged from the chamber 32 through the openings 29, to the chamber 34 through the openings in the partition 28.

By locating the comminuting chambers 2,

4, 32, 34, adjacent the .ends of the mill, the charges of comminuting bodies 35, 36, may be made of sufficient volume to produce most eflicient grinding without overstraining the shell of the mill. The weight of the total charge may be retained within the limits of strength of the driving mechanism and ofthe available power. If so desired, the length of the comminuting chambers may be made such by adjustment of the division partitions, that a light charge of grinding bodies may be placed in the intermediate chambers 3, 33, without overstraining the shell or the driving mechanism of the milli The screw conveyer serves to rapidly urge the material from one of the comminuting chambers to the other in order to prevent I accumulation of an excessive weight of material in portions of the mill remote from the supports.

It will thus be noted that with the use of the present invention, relatively light mills may be readily reconstructed to increase their capacity and efiiciency without danger of injuringthe mills or the driving mechanisms thereof and without expensive alterations in the construction. While the greater portion of the tube mills installed have drums of uniform diameter throughout their length, the invention is also applicable in cases where different portions of the mill are of different diameters, the primary object being to provide means for confining the weight of the heavy charges of grinding bodies to the portions of the mill adjacent the supports thereof, without requiring any explensivc change in the construction of the m1 s.

It should be understood that it is not desired to be limited to the exact details of construction shown and described, for obvious modlfications Wlll occur to a person skilled in the art.

It is claimed and desired to secure by Letters Patent 1. In a tube mill capable of grinding throughout its length with relatively light comminuting bodies only, means for increasing the grinding capacity of said mill including means for confining the charge to be ground including relatively heavy comminuting bodies to the spaces in the ends of the mill leaving a space in the center of the mill containing no comminuting bodies, of such extent and position that the mill will be capable of sustaining the load.

2. In an end-trunnion-supported tube-mill adapted to support a grinding charge of material including relativel light comminuting bodies throughout 1ts length and capable of supporting a grinding charge of material including relatively heavy comminuting bodies through a fraction of its length only, means for driving said mill capable of providing for. a given maximum amount of power, and means, when relatively heavy comminuting bodies are used, for confining the charge to the spaces in the ends of the mill leaving a space in the center of the mill of such extent that the grinding charge will not impose a load greater than said given maximum amount of power.

3. In an end-trunnion-supported tubemill adapted to support a grinding charge of material including relatively light comminuting bodies throughout its length and capable of supporting a grinding charge of material including relatively heavy comminuting bodies through a. fraction of its length only, and means, when relatively heavy comminuting bodies are use-d, for confining the charge'to the spaces in the ends of the mill leaving a space in the center of the mill of such extent that the load on the trunnions will not be greater than the maximum permissible load.

4. In an e-nd-trunnion-supported tube-mill adapted to support a grinding charge of material including relatively light comminuting bodies throughout its length and capable of supporting a grinding charge of material including relatively heavy comminutingbodies through a fraction of its length only, and means, when relatively heavy comminuting bodies are used, for confining the charge to the spaces in the ends of the mill leaving a space in the center of the millgreater than either of said grinding spaces, said means including removable partitions. v

5. In an end-trunnion-supported tube-mill capable of supporting a grinding charge of material including relatively light comminuting bodies throughout its length but incapable of supporting a grinding charge of material including relatively heavy comminuting bodies throughout its length, means for driving said mill capable of providing for a. given maximum amount of power, means for confining the charge to be ground including relatively heavy comminuting bodies to the spaces in the ends of the mill leaving a space in the center of the mill of such extent thatthe grinding charge will not impose a load greater than said given maximum amount of power; and means for conveying, without grinding, said material through said central space.

6. In an end-trunnion-supported tube-mill capable of supporting a grinding charge of rraterial including relatively light comminuting bodies throughout its length but incapable of supporting a grinding charge of material including relatively heavy comminuting bodies, me-ans for confining the charge to be. ground including relatively heavy comminuting bodies to the spaces in the ends of the mill leaving a space in the center of the mill of such extent that the load .on the trunnions will not be greater than the maximum permissible load, and means for conveying, without grinding, said material through said central space.

7 In an end-trunnion-supported tube-mill capable of supporting a grinding charge of material including relatively light comminuting bodies throughout its length but incapable of supporting a grinding charge of material including relatively, heavy comminuting bodies throughout its length, means for confining the charge to be ground including relatively heavy comminuting bodies to the space in the ends of the mill leaving a space in the center of the mill greater than either of said grinding spaces, and means for conveying, wlthout grinding, said material through said central space.

8. The method of more eificiently grinding in an end-trunnion-supported tube-mill adapted to support a charge including relatively light comminuting bodies throughout its length but incapable of supporting a charge of relatively heavy comminuting bodies throughout its length, when loaded substantially to the axis of the mill, which ing in an end-trunnion-supported tube-mill,

adapted to support a charge including relatively light comminuting bodies throughout its length but imcapable of supporting a charge of relatively heavy comminuting bodies throughout its length, when loaded substantially to the axis of the mill, which comprises introducing the material to be ground at one end of the mill and charging the mill to a desired fraction only of the distance from said end to the centerof the mill, grinding said material with relatively heavy comminuting bodies, conveying, without grinding, said material to the other end of the mill and there charging the mill, for maximum grinding capacity, substantially the same fraction of the distance from said other end of the mill as for the first named end and grinding said material with relatively heavy comminuting bodies.

10. A tube mill comprising a longitudinally extended, rotary container constructed to sustain an operative load of comparatively light grinding bodies throughout its length and practically incapable of sustaining throughout its length the weight of a full operative charge of relatively heavy grinding bodies therein, said container being provided with grinding chambers at its feed and discharge ends and with a peripherally closed, non-grinding conveying chamber extending from the chamber at the inlet end of said container to the chamber at the outlet end thereof.

11. A tube mill consisting of a container constructed to sustain an operative load of comparatively light grinding bodies throughout its length and provided, with screen partitions forming end grinding chambers and an intermediate conveying chamber, the peripheral wall of the said intermediate chamber being incapable of sustaining a full charge of grinding bodies therein, and said container having end inlet and outlet openings.

12. In a tube mill adapted to grind throughout its length with relatively light comminuting bodies, means for driving said mill capable of providing for a given maximum amount of power, said amount being less than would be needed for driving the mill when loaded throughout its length with relatively heavy comminuting bodies, and means, when relatively heavy comminuting bodies are used, for confining the charge to the spaces in the ends of the mill leaving a space in the center of the mill of such extent that the grinding charge will not impose a load greater than said given maximum amount of power.

13. In a tube mill adapted to grind throughoutits length with relatively light comminuting bodies, means for driving said mill capable of providing for a given maximum amount of power, said amount being less than would be needed for driving the mill when loaded throughout its length with relatively heavy comminuting bodies, means, when relatively heavy comminuting bodies are used, for confining the charge to the spaces in the ends of the mill leaving a space in the center of the mill of such extent that the grinding charge will not impose a load greater than said givencmaximum amount of power, and means for conveying, without grinding, said material through said central space.

In testimony whereof, the signature of the inventor is aflixed hereto.

RAY C. NEWHOUSE. 

